#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>

int main()
{
	FILE* pf = fopen("test.dat", "w");
	if (pf == NULL)
	{
		perror("fopen");
		return 1;
	}
	fputc('b',pf); 


	fclose(pf);
	pf = NULL; 
	return 0;
}

